/***
 * Copyright 2002-2010 jamod development team
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * 
 * Original implementation by jamod development team.
 * This file modified by Charles Hache <chache@brood.ca>
 ***/

package net.wimpi.modbus.msg;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;

import net.wimpi.modbus.util.BitVector;
import net.wimpi.modbus.Modbus;

/**
 * Class implementing a <tt>ReadInputDiscretesResponse</tt>. The implementation
 * directly correlates with the class 1 function <i>read input discretes (FC
 * 2)</i>. It encapsulates the corresponding response message.
 * <p>
 * Input Discretes are understood as bits that cannot be manipulated (i.e. set
 * or unset).
 * 
 * @author Dieter Wimberger
 * @version @version@ (@date@)
 */
public final class ReadInputDiscretesResponse extends ModbusResponse {

	// instance attributes
	private int m_BitCount;
	private BitVector m_Discretes;

	/**
	 * Constructs a new <tt>ReadInputDiscretesResponse</tt> instance.
	 */
	public ReadInputDiscretesResponse() {
		super();
		setFunctionCode(Modbus.READ_INPUT_DISCRETES);
	}// constructor

	/**
	 * Constructs a new <tt>ReadInputDiscretesResponse</tt> instance with a
	 * given count of input discretes (i.e. bits). <b>
	 * 
	 * @param count
	 *            the number of bits to be read.
	 */
	public ReadInputDiscretesResponse(int count) {
		super();
		setBitCount(count);
	}// constructor

	/**
	 * Returns the number of bits (i.e. input discretes) read with the request.
	 * <p>
	 * 
	 * @return the number of bits that have been read.
	 */
	public int getBitCount() {
		return m_BitCount;
	}// getBitCount

	/**
	 * Sets the number of bits in this response.
	 * 
	 * @param count
	 *            the number of response bits as int.
	 */
	public void setBitCount(int count) {
		m_BitCount = count;
		m_Discretes = new BitVector(count);
		// set correct length, without counting unitid and fc
		setDataLength(m_Discretes.byteSize() + 1);
	}// setBitCount

	/**
	 * Returns the <tt>BitVector</tt> that stores the collection of bits that
	 * have been read.
	 * <p>
	 * 
	 * @return the <tt>BitVector</tt> holding the bits that have been read.
	 */
	public BitVector getDiscretes() {
		return m_Discretes;
	}// getDiscretes

	/**
	 * Convenience method that returns the state of the bit at the given index.
	 * <p>
	 * 
	 * @param index
	 *            the index of the input discrete for which the status should be
	 *            returned.
	 * 
	 * @return true if set, false otherwise.
	 * 
	 * @throws IndexOutOfBoundsException
	 *             if the index is out of bounds
	 */
	public boolean getDiscreteStatus(int index)
			throws IndexOutOfBoundsException {

		return m_Discretes.getBit(index);
	}// getDiscreteStatus

	/**
	 * Sets the status of the given input discrete.
	 * 
	 * @param index
	 *            the index of the input discrete to be set.
	 * @param b
	 *            true if to be set, false if to be reset.
	 * @throws IndexOutOfBoundsException
	 *             if the given index exceeds bounds.
	 */
	public void setDiscreteStatus(int index, boolean b)
			throws IndexOutOfBoundsException {
		m_Discretes.setBit(index, b);
	}// setDiscreteStatus

	public void writeData(DataOutput dout) throws IOException {
		dout.writeByte(m_Discretes.byteSize());
		dout.write(m_Discretes.getBytes(), 0, m_Discretes.byteSize());
	}// writeData

	public void readData(DataInput din) throws IOException {

		int count = din.readUnsignedByte();
		byte[] data = new byte[count];
		for (int k = 0; k < count; k++) {
			data[k] = din.readByte();
		}

		// decode bytes into bitvector
		m_Discretes = BitVector.createBitVector(data);
		m_BitCount = count;

		// update data length
		setDataLength(count + 1);
	}// readData

	public String toString() {
		return "ReadInputDiscretesResponse - Coils: " + getBitCount();
	}

}// class ReadInputDiscretesResponse
